Analysis of Control Strategies for Thermally Linked Distillation Columns.

A procedure for analyzing control strategies for two distillation columns thermally linked according to the feed-split configuration is presented for the purpose of determining control schemes with a low degree of interaction. The method employed performs an analysis of the interactions between the control loops according to two techniques - namely, the relative gain matrix method and the dynamic interaction column method. The former method is based on data obtained in the steady state, while the latter method takes into account the dynamic characteristics of the open-loop system and also allows for the presence of controllers and decouplers. The validity of the noninteracting control schemes identified has been verified by dynamic simulation.